BloomCombine.fx does not work in NeonShooter

[rccarlson]

For some reason, the bloom effect is not working in the NeonShooter sample. All stages work until the final combine step, where the s1 sampler is all black and does not combine with the blurred layer.

[rccarlson]

Solution: https://community.monogame.net/t/how-to-achieve-a-bloom-effect-on-2d-textures/2614/8